Safety-Aware UAVs Formation Scheme for Guiding UGVs through Obstacle-Laden Environments

Abstract

Using unmanned aerial vehicle (UAV) formations to guide unmanned ground vehicles (UGVs) through unstructured obstacle-laden areas leads to highly efficient execution of tasks such as the transportation of supplies. However, existing methods fail to efficiently plan obstacle-avoidance strategies for the entire UAV-UGV swarm. Additionally, the formation controller and planner are isolated, resulting in the degradation of formation tracking accuracy, which presents potential security risks. This paper proposes a novel UAV formation scheme that integrates safe corridor (SC) generation, trajectory fitting, and formation tracking to ensure operational safety. The scheme employs a novel line-of-sight (LOS) mechanism to optimize A*-planned waypoints, generating the SC as an obstacle-avoidance strategy. A minimum snap trajectory is fitted to the optimized waypoints with SC constraints. Bridged by the trajectory, the scheme develops a rigid-graph-based controller (RGC) to track the planning result, enabling dynamic formation maneuvering within the SC. Consequently, the proposed UAV formation scheme achieves obstacle-avoidance guidance by restricting the UGVs to the formation projection. The validation results demonstrate that the proposed scheme exhibits enhanced robustness and superior planning capabilities compared to traditional methods.